相对于高阶工作模式的单腔回旋管,同轴腔回旋管具有缓解模式竞争,提高单模工作的稳定性,以及增大功率容量的优点,宜用于受控热核聚变中的电子回旋共振加热和电子回旋电流驱动而受关注.详细地研究了工作频率为 170 GHz,TE34,11模同轴腔回旋管的结构参数、电子束参数及腔壁损耗对注-波互作用的影响.首先对 170 GHz兆瓦级功率模式选择进行分析,给出了工作模式.再次,基于时域自洽非线性理论,编写了时域单模稳态注-波互作用程序,分析了电流、磁场强度和腔壁欧姆损耗对互作用的影响,并对工作参数进行了优化.模拟结果表明: 当电子束电流为 68 A,工作电压为 65 kV,引导磁场强度为 6. 58 T时,可获得 2. 18 MW的输出功率, 49. 23 %的效率,外腔壁上的欧姆损耗密度峰值为 1. 94 kW/cm2,内导体表面的小于 0. 15 W/cm2; 互作用效率随速度零散增大而降低,输出频率向下偏移; 电子注厚度对互作用也有相似的影响.

Relative to the single-cavitygyrotrons operatingin high-order mode,the coaxial cavitygyro-trons have the advantages of reducing mode competition,improvingthe stability of single mode opera-tion and increasing the power capacity. Therefore,the coaxial cavity gyrotrons are more suitable for electron cyclotron resonance heating and electron cyclotron current drivingin controlled thermonuclear fusion and attract much attention. The effects of structure parameters,electron beam parameters and ohmic losses on the beam-wave interaction of a coaxial cavity gyrotron operating at 170 GHz, TE34,11 mode were investigated in detail. Firstly,the mode selection of 170-GHz MW-class gyrotrons wasanalyzed and mode TE34,11 was chosen asthe operating mode. Secondly,based on the time-depen-dent self-consistent nonlinear theory,a time-domain single-mode steady-state code was written to studythe beam-wave interaction. Theinfluencesofthebeam current,the magneticfield andtheohmic losses on the cavity walls were analyzed and the operatingparameters were optimized. The simulation results show that when the voltage,the beam current and the axialguiding magnetic field are designed to be 65 kV,68A and 6.58 T,an output with 2.18 MW power and 49.23 % efficiency can be ob-tained, the peak ohmic loss density on the outer wall of the cavity is 1.94kW/cm2, and the peak ohmic loss density on the insertis less than 0.15W/cm2. The interaction efficiency decreases with the in-crease of electron velocity spread, and the output frequency shifts downward. The thickness of electron beam has similar effects on the interaction.